Hall devices are sensors that respond to a magnetic field. They typically suffer from offset error: the offset error is a non-vanishing output signal at zero applied magnetic field. Vertical Hall devices (VHall) mainly respond to a magnetic field parallel to the surface of the substrate.
A number of different designs of vertical Hall devices are known, yet many of them are not apt for the so-called spinning current method (or achieve only poor offset-cancelling performance) and suffer from low magnetic sensitivity and large electric fields. Typically, several contacts are placed on the surface of the substrate in such a way that current can flow in semicircles between two supply contacts while a sense contact is placed between these supply contacts and taps the Hall voltage that is generated by the current diving underneath the sense contact.
Depending on the electronic devices to be manufactured and/or the semiconductor manufacturing technology, a highly conductive, buried layer may be present within the semiconductor substrate. A buried layer is a heavily doped region of the opposite conductivity type as the substrate. The buried layer is placed beneath the active device regions by ion implantation. Both the doping and damage characteristics of the buried layer influence device performance. Buried layer substrates may be formed by, for example, high-energy implantation and rapid thermal annealing. When a buried layer is present within the semiconductor substrate, this typically limits the available depth of a Hall effect region of a vertical Hall device.